I was going to post this suggestion, but you got there before me, so you've earned a +1. Destiny badly needs a map to make navigation easier. I never really got lost, but I did end up back in the same places when I was trying to explore the map and find certain areas. As someone else said, custom waypoints would be a good feature, but I think being able to mark your map so you can revisit interesting areas would be an excellent idea, too. Being able to use multiple marks and being able to scroll through them would also not go unappreciated, and giving them rudimentary tags like "loot" or "cave" would make it even easier to navigate, especially if you have a multitude of marks.